Improvement in electric commutators



UNITED STATES PATENT OFFICE, r

LEROY B. FIRMAN, OF CHICAGO, ILLINOIS.

IMPROVEMENT lN ELECTRIC COMMUTATORS.

Specification forming part of Letters Patent No. 75,743, dated March 24, 1868.

To all lwhom it may concern:

Be it known that I, LEROY B. FIRMEN, of Chicago, in the county of Cook and State of lllinois, have invented a new and useful Improved Telegraphic Cireuit-Oommutator; and I do hereby declare and make known that the following is a full, clear, and exact description of the same, reference being had to the accompanying drawings, and the letters and figures of reference marked thereon, which form part of this specication.

Although my said invention is of a general application for the purpose of opening and closing telegraphic circuits, still it is especially applicable to the purpose of breaking the circuits in ire-alarn1 telegraphic systems, and said invention is represented in the drawings as being applied in such connection.

The nature of my said invention consists in constructing a wheel whose circumference is unbroken by pins or projections, certain appropriate sections thereof being composed of gutta-percha, hard rubber, or some other suitable non-conductor, whereby the revolution of at suitable times, bringing said non-conductingsurfaces in contact with the poles of the wires, will break the circuit and give the appropriate signals to the central oflice, as desired.

To enable those skilled in the art to understand how to construct and use my said invention, I will proceed to describe the same with particularity, reference being had to the aforesaid drawings in so doing, in which- Figure l represents a front view of my said invention; Fig. 2, a side view or elevation of the same; Fig. 3, a central section of the cominutating wheel or disk 5 and Fig. 4 is a rear view of the said wheel.

Similar letters of reference in the several gures denote the same parts of my invention.

A represents au open signal-box,from which the signal or alarm is to be transmitted to the central oce, which may be constructed in the usual manner, and in which the signaling apparatus is contained. The wire a enters the box and is attached to a metallic plate, C, which is so arranged that its end presses upon and remains in contact with the plate or disk D,

which is of brass or some other suitable conducting material.

E represents another metallic springplate, whose point l presses upon and remains Iin contact with the periphery of the circuit commutating-wheel W, which consists of a cogged pinion, K, a giitta-percha disk, L, and the aforesaid metallic disk D, which are firmlysecured together by means of screws s s, as shown. Thus it will readily be seen that when the edge of the metallic plate D is in contact with the point d of the spring E the electric current passes through said plate D from the end ofl the spring C to the spring E, and then out upon the wire a', as indicated by the arrows. The entering-wire a is also connected with a metallic plate, B, and the exit-wire a', in like manner, is connected with a spring-plate, F, upon which last-named plate a post, G, is fixed, and so arranged as to project out from the box, so that when the door ofthe box is closed the post presses the spring F down upon the plate B, thus forming a cut-oft` for the circuit when not in use, so that any accidental displacement of the commutator will not break the circuit and interfere with the operation of the other boxes on the same line.

It will be observed that in the circumference of the metallic diskD recesses l 2 3 4 are cut, so that said disk cannot at said points come in contact with the pole E at the point d. At said points the rubber or gutta-percha disk L rises up, so as to receive the point d and prevent its pressing in upon the face of said recesses. On the other hand, at all parts ofthe disk D which are desired to remain and be in contact with said point d. the gutta-percha is cut away, so as not by any possibility to prevent the desired contact which closes the circuit. Thus at all times during the revolution of the commutator a plain even periphery is presented to the'point d, while at the same time the circuit is manipulated as desired, said slots or recesses l 2 3 et being varied to suit the signal required.

The points where the metal disk D is cut away are prevented from lying in contact with the gutta-percha by chamferin g or beveling ofl'' the latter disk so as to leave a space between, so that no dust or Wearings of the brass can pass to the non-conducting disk to coat its surface and endanger the accurate operation ot' the apparatus.

The gear-wheel R is provided with a hollow hub, I?, around which the disks L and D are placed, and the whole is then arranged upon a spindle, M, upon which it revolves.

A gear-wheel, H, supported upon a shaft or spindle, N, engages with the cogs K upon the commutator, and is turned by a crank or handle, I, upon which is a weight, to cause the commutator, when at rest, to always assume such a position as to close the circuit through the poles C and E.

Having described the. construction, operation, and nature of my invention, I will now specify what I cla-ini and desire to secure by Letters Patent.

A coininutating,` wheel composed of two plates, circular or annular, one of a conduct ing and one of a non-conducting;` material, L D, when alternate sections of the two plates or their peripheries are moved in contact with the point d, and when the points of alternation are chamfered off and kept from contact with each other, iu the manner and for the purposes specied and described.

LEROY B. FIRMAN.

Witnesses:

W. E. MAUS, L. L. GOBURN. 

